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  1. (*=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent Database.Persist

    Assign a field by multiplication (*=).

    Examples

    multiplyAge :: MonadIO m => ReaderT SqlBackend m ()
multiplyAge = updateWhere [UserName ==. "SPJ" ] [UserAge *=. 2]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+--------+
|id   |name |age     |
+-----+-----+--------+
|1    |SPJ  |40 -> 80|
+-----+-----+--------+
|2    |Simon|41      |
+-----+-----+--------+

  2. (+=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent Database.Persist

    Assign a field by addition (+=).

    Examples

    addAge :: MonadIO m => ReaderT SqlBackend m ()
addAge = updateWhere [UserName ==. "SPJ" ] [UserAge +=. 1]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+---------+
|id   |name |age      |
+-----+-----+---------+
|1    |SPJ  |40 -> 41 |
+-----+-----+---------+
|2    |Simon|41       |
+-----+-----+---------+

  3. (-=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent Database.Persist

    Assign a field by subtraction (-=).

    Examples

    subtractAge :: MonadIO m => ReaderT SqlBackend m ()
subtractAge = updateWhere [UserName ==. "SPJ" ] [UserAge -=. 1]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+---------+
|id   |name |age      |
+-----+-----+---------+
|1    |SPJ  |40 -> 39 |
+-----+-----+---------+
|2    |Simon|41       |
+-----+-----+---------+

  4. (/<-.) :: forall v typ . PersistField typ => EntityField v typ -> [typ] -> Filter v

    persistent Database.Persist

    Check if value is not in given list.

    Examples

    selectSimon :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSimon = selectList [UserAge /<-. [40]] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|2    |Simon|41   |
+-----+-----+-----+

  5. (/=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent Database.Persist

    Assign a field by division (/=).

    Examples

    divideAge :: MonadIO m => ReaderT SqlBackend m ()
divideAge = updateWhere [UserName ==. "SPJ" ] [UserAge /=. 2]
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+---------+
|id   |name |age      |
+-----+-----+---------+
|1    |SPJ  |40 -> 20 |
+-----+-----+---------+
|2    |Simon|41       |
+-----+-----+---------+

  6. (<-.) :: forall v typ . PersistField typ => EntityField v typ -> [typ] -> Filter v

    persistent Database.Persist

    Check if value is in given list.

    Examples

    selectUsers :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectUsers = selectList [UserAge <-. [40, 41]] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+
|2    |Simon|41   |
+-----+-----+-----+

    selectSPJ :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSPJ = selectList [UserAge <-. [40]] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

  7. (<.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent Database.Persist

    Less-than check.

    Examples

    selectLessAge :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectLessAge = selectList [UserAge <. 41 ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

  8. (<=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent Database.Persist

    Less-than or equal check.

    Examples

    selectLessEqualAge :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectLessEqualAge = selectList [UserAge <=. 40 ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

  9. (=.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Update v

    persistent Database.Persist

    Assign a field a value.

    Examples

    updateAge :: MonadIO m => ReaderT SqlBackend m ()
updateAge = updateWhere [UserName ==. "SPJ" ] [UserAge =. 45]
    Similar to updateWhere which is shown in the above example you can use other functions present in the module Database.Persist.Class. Note that the first parameter of updateWhere is [Filter val] and second parameter is [Update val]. By comparing this with the type of ==. and =., you can see that they match up in the above usage. The above query when applied on dataset-1, will produce this: 
    +-----+-----+--------+
|id   |name |age     |
+-----+-----+--------+
|1    |SPJ  |40 -> 45|
+-----+-----+--------+
|2    |Simon|41      |
+-----+-----+--------+

  10. (==.) :: forall v typ . PersistField typ => EntityField v typ -> typ -> Filter v

    persistent Database.Persist

    Check for equality.

    Examples

    selectSPJ :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSPJ = selectList [UserName ==. "SPJ" ] []
    The above query when applied on dataset-1, will produce this: 
    +-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+

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